New Updates to Equipment Productivity
and Reliability Standards -SEMI E10 and SEMI E79

In
recent Cycle 2, 2014 voting, the SEMI Standards community approved simultaneous
revisions to SEMI E10, Specification for
Definition and Measurement of Equipment Reliability, Availability, and
Maintainability (RAM) and Utilization and SEMI E79, Specification for Definition and Measurement of Equipment Productivity.
SEMI E79, in particular, was well past its mandatory five-year review cycle and
in need of technical and editorial updates as well as a thorough review by the
user community. It was the objective of the Equipment RAMP (Reliability,
Availability, Maintainability, and Productivity) Metrics Task Force (TF), that
upon approval of these two letter ballots, that the Documents will be mutually
consistent and sufficiently clear and complete requiring no major technical content
changes until the next mandatory five-year review cycle.

A
primary accomplishment of the revision to SEMI E10 is the introduction of a
substantial set of example calculations as a new section, Related Information
2. This example covers a scenario for a five-module multi-path cluster tool
(MPCT) with three processing equipment modules, a handler equipment module, and
a mainframe equipment module organized into two intended process sets (IPSs).
The scenario exercises key features of the SEMI E10 state tracking and metrics.
An event-by-event description explains how equipment module events become
equipment module states, how equipment modules states become IPS states, and
how the IPS states become states for the MPCT. All fundamental quantities for
the metrics and the metrics themselves are calculated for all equipment
systems, including the individual equipment modules, the IPSs, and the MPCT.

The SEMI
E10 revision added two other related information sections. Related Information 3
presents reporting conventions taken from the now inactive SEMI E58 (ARAMS)
Document, including standard color codes for the SEMI E10 states and updated
numerical codes and names of some SEMI E10 substates allowing interested users
to access this content in SEMI E10. Related Information 4 presents guidance on
where to draw productive time boundaries.
This is accomplished by referencing equipment automation state models in
other SEMI Standards and identifying when the SEMI E10 productive state (PRD) is
active in those models.

Regarding
technical changes in SEMI E10, none of the definitions of any metrics have
changed and there are no new metrics, nor any metrics removed. The IPS state
logic was revised slightly to make the IPS productive only when processing equipment
modules are productive, making SEMI E10’s treatment of MPCTs more consistent
with SEMI E79’s treatment. And through improved terminology, the Document now
makes clear distinctions between the SEMI E10 states and the accumulated time
in each of those states (e.g., the productive state versus productive time).

A
primary accomplishment of the revision to SEMI E79 is the introduction of four
new metrics under one subsection called Loss Metrics. These productivity loss metrics
are:

availability loss,

operation loss,

rate loss, and

assignable quality loss.

These
four metrics support the comparison of loss categories to each other using
total time as a common denominator, and the values of these metrics plus OEE (overall
equipment efficiency) add to 100% by definition. They are calculated using the
same fundamental quantities used in the existing efficiency metrics, and
present no new tracking requirements.
The example calculations section, Related Information 1, has been
extended to demonstrate these new metrics for a noncluster tool and for an MPCT.

Among several
technical clarifications, the revision to SEMI E79 removed the term “virtual
machine” previously used to describe an individual processing equipment module
plus its related handling resources. Instead SEMI E10 and SEMI E79 now consistently
require that productive time and theoretical productive time must include time
for loading and unloading of units for all equipment systems. Also, the
supplemental metric in Appendix 1 previously called Engineering OEE has been
more accurately renamed as Optimized-Recipe OEE.

This
simultaneous passage of revisions to both SEMI E10 and SEMI E79 has been in the
works for a several years, since the two separate TFs for revising E10 (the E10
Revision TF) and E79 (the Equipment Productivity Metrics TF) were consolidated
into the current Equipment RAMP Metrics TF. Having achieved this milestone, this
TF is now turning its attention toward technical education of the user community
and away from major technical revisions.

Get Involved

If you are interested in participating in the Equipment RAMP Metrics Task
Force, the Metrics Global Technical Committee or would like more information on
the SEMI International Standards Program, please contact Michael Tran from SEMI
at 1.408.943.7019 or mtran@semi.org.